In the field of Neural Prostheses, there is a need for multi-channel recording systems that are implantable under the scalp and that can record from multiple electrodes implanted in human cortex. These systems must have longevity, reliability and high bandwith for recording sharp transient neural activity. Our aim in this proposal is to build on our experience with a 2 channel system, a recently developed eight channel system, and take this to the next level of a 128 channel system, all on the same small footprint. Our specific aims are to (a) design high-density integrated circuit amplifiers for recording biological signals, (b) design a multiplexing system, and (c) fabricate the integrated circuit in the MOSIS foundry and bench test. Longer-term aims are to (i) Incorporate the IC and MUX into our recently completed Hybrid Implantable Electronic Device retaining use of the power induction module, calibration signal and FM transmitters. We would also develop a demultiplexer. (ii) Improve the power induction coil so that it can be used at a distance from the subjects' head or body part containing the power induction receiver coil. This will also involve development of a power amplifier such as an E type amplifier. (iii) Incorporate this IC into LCP based packaging or other substrate and inter-connect technology. (iv) Implant these devices into monkeys after extensive bench testing in preparation for human as well as animal implantation. [unreadable] We expect this effort to eventually result in a recording system that will be the standard for human neural prostheses implantations, thus contributing significantly to the alleviation of human suffering and disability. [unreadable] [unreadable]